Flexible tube sheet for thermic siphon boilers



June 27, 1933. l H. v, STEVENS 1,915,455

FLEXIBLE TUBE SHEET FOR THERMIC SIPHON BOILERS Filed March 19, 1951 ATTORNEY.

Patented June 27, 1933 PATENT OFFICE HENRYKV. STEVENS, OF TOPEKA, KANSAS FLEXIBLE TUBE SHEET' FOR THERMIC SIPHON BOILERS Application filed March 19, 1931. Serial No. 523,764.

'I his invention relates tosteam boilers and more particularly to those of that character employing Itherinic siphons for circulating water through the fire box of the boiler.

5 In boilers .ofthis type the thermic siphons being located directly in the lire box, heat and cool faster than the other parts of the boiler and due to the fact that they yhave little or no inherent flexibility the difference 1 0 in expansion and contraction places great strains on the necks of the siphons and they soon fracture or tear themselves loose where they attach to the inner sheets of the fire box, due tothe fact that these sheets are so rigidly 5 mounted.

It is therefore the principal object of this invention to prevent rupturing of the siphons by .providing means whereby the supporting sheet may flex to accommodate for the difference in expansion and contraction.

In accomplishing this and other ob]ects of the invention, I have provided improved details of structure, the preferred forin of which kis illustrated in the accompanying 2,5 drawing wherein:

Fig. l is aV longitudinal sectional view through the fire box portion of a boiler embodying my invention.

Fig. l2 is a cross section of the boiler on the 30 line 2 2, Fig. 1. f

Fig, 3 is a detail sectional View of a portion lof a boiler showing a slightly modified form of my invention.

Referring more in detail to the drawing 1 designates a locomotive boiler comprising a. barrel portion 2 and a fire box portion 3 which includes a back sheet 4:, a roof sheet 5 and casing sheets 6 and 7, constituting the outer walls of the re box. The inner walls of the lire box comprise a crown sheet 8, side sheets 9 and 10 anda door sheet 11 spaced from the corresponding sheets of the boiler and a flue or tube sheet 12 forming the forward end ofl the fire box and supporting the rear ends of the fire tubes 13.

The lower end of the tube sheet 12 extends downwardly and rearwardly kbelow the barrel portion vof the boiler as at 14 and spaced therefrom is a throat sheet 15 connect- 50 ing the lower barrel portion of the boiler with a mud ring 16 extending circumferentially of the fire box and connecting the fire box sheets at their lower ends, as clearly illustrated in Figs. 1 and 2. The inner and outer walls of the fire box are braced by the usual stay bolts 17 and the crown sheet is rigidly supported from the roof sheet by the usual stays 18.

Extending through the re box are water siphons 19 for circulating water from the throat 2O which is formed by the inclined portion 1101i' the tube sheet and the throat sheet 15, the steaming space 21 between the roof and crown sheets, as in ordinary boiler construction employing water siphons.

The water siphons 19 usually comprise substantially flat funnel-shaped members having open upper ends 22 connected in longitudinal slots 23 formed in the crown sheet and having forwardly and downwardly in- 7o clined tube portions 24 terminating in tubular necks 25.

The necks 25 are connected in openings formed in the inclined portion of t e tube sheet at a point between the mud ring 16 and 55 the lower re tubes 13. The tube sheet is usually provided with an annularly extending expansion diaphragm 26 encircling each Siphon neck 25, as clearly shown in F ig. 2.

Since the upper ends of the siphons are rigidly supported by the stay rods 18, the major expansion and contraction of the siphons takes place in a downward direction and toward the inclined portion of the tube sheet. The diaphragme 26 are supposed to "S5 compensate for movement of the necks of the siphons with relation to the tube sheet. However, it has been found from actual practice that the diaphragms 26 do not completely kaccomplish the purpose for which they are intended, since the tube sheet is so rigidly mounted the diaphragms 26 cannot provide sufficient iexibility to'compensate for the downward expansion of the siphons.

v In other words, the relative vertical movement of the tube sheet is practically nihil and when expansion and contraction of the siphon takes place the axis of the necks 25 tends to move vertically with relation to the axis of the openings formed in the tube sheet, thus A tending to bend the necks of the siphons so that after the boiler has been in use, the constant bending fractures and cracks the necks of the siphons adjacent their juncture with the body portions thereof or the necks tend to break through their connections with the j tube sheet.

As above mentioned, it is the object of the present invention to accommodate the tube sheet for vertical movement of the siphons and to provide flexibility whereby the tube sheet can move vertically and laterally with relation to the necks of the siphons'tov relieve the bending tendency of the necks.

In accomplishing this object I provide the lower edge of the tube sheet with an inwardly formed expansion rib 27 extending across the width of the sheet at a point above the mud ring 16 so that the curved portion yof the rib may flex and compensate for the downward movement ofthe siphons. Y

Inporder to additionally relieve the strains on the lower'end of the tube sheet and to provide additional flexibility, I provide an inwardly extending-expansion rib 28 extending Vin an arc belowv the lower bundle of fire tubes 13, as shown in Fig. 2, which cooper.- atesr with the rib 27 to provide a relatively Boating plane section of the tube sheet to which the siphons are attached. f

It also may be desirable to provide an expansion rib 29 in the crown sheet adjacent its juncture 'with the tube sheet as'shown in Fig. 1. The' stay bolts w8() which extend through the' throat 2() :tor tying the floating flexible portion of the tube sheet with the throat sheet are preferably of .the flexible type so that the inclined portion of the tube sheet may move independently .with relation to the throat sheet.

In aboiler constructed` and assembled as described, the expansion and contraction` which takes place in the siphons tend to move the necks of the siphons longitudinally and downwardly with relation tothe tube sheet, and the movement is compensated by a corresponding shifting of the floating section due tothe expansion ribs 27 Tand 28, and no strain is exerted on the diaphragms 26 or the necks of the siphons i In Fig. 3J is illustrated a modified form of throat 31 wherein the throat sheet extends -in avertical'plane'. In this construction thev rib 32 whichprovides flexibility-of the tube sheet 33 curves inwardly into thefire box from its point of attachment to the mud ringl as at 34 and is then inclined as at 35 to merge into the plane of the tubesheet to provide an,

inclined portion 36 similar to the inclined portion of the tube sheet in the boiler construction illustrated in Figs. 1 and 2.

WhileI have illustrated a boiler provided with three water siphons, it is'apparent 'that my inventionmay Abe employed in boilers having one or more siphons, the number, of

c)ourse, depending on the width of the re What I claim and desire to secure by Letters Patent is:

1. Ina boiler including a iire box comprising spaced inner and outer sheets, a mud ring connecting the lower edges of the inner and outer sheets, and a siphon having substantially no inherent flexibility to compensate for expansion and contraction thereof and having its upper end supported by an upper inner sheet of the fire box, an inwardly inclined diaphragm section formed on the lower portion, of one of the inner sheets for mounting the lower end of said siphon, and an outwardly and-downwardly curved portion formed. on the lower edge of said cliaphragm and extending substantially across the width of said inner sheetfor attachment to the mud ring whereby downward thrust produced byrexpansion of said siphon and imparted to said diaphragm section acts to 'flex said attaching portion."

2.7In a boiler including a fire boxcomprising spaced inner' and outer sheets, a ymud ring connecting the loweredges of the inner and outer sheets, a siphon supported by an upper inner sheet of the fire box and having substantially no inherent flexibility to compensate for expansion and contraction thereof, an inwardly inclined'diaphragm section formed on the lower portion ofrone of the inner sheets and extending across the width of the tire box, for mounting the lower end of said siphon and arranged so that the plane of said section is oiset inwardlyfrom the mud ring,.and flexible means for attaching the lower edge of said diaphragm to the mud ringv for closing the space between the section and the mud ring whereby downward thrusts vproduced by expansion of said siphon are offset laterally from said 'mud ringto provide free downward movement of the diaphragm section in the planey thereof.

3. In a. boiler including a fire box comprising spaced inner and outer sheets, a mud ring connecting the lower edges of the inner and outer sheets, a siphon having substantially no inherent flexibility to compensate for expansiony and contraction thereof and having its upper and lower ends supported by a pairof the inner 'sheets adjacent the upper and lower portions of the tire box respectively,land an outwardly and downwardly curved flange portion* formed on the lower edge of the sheet supporting the lower end of the siphon and extending substantially across the widtli'thereof for ofsetting the lower edge of the sheet laterally of said mud ring toward the interior of the tire box Whereby downward thrusts produced by expansion of said siphon are offset laterally from said mud ring and absorbed byl said curved flange portion. v

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with a Siphon having substantially no inherent flexibility to compensate for expansion and contraction thereof, a tube sheet for the fire box including a downwardly and inwardly inclined diaphragm section extending across the width of the tube sheet for mounting the lower end of said Siphon, means formed in said tube sheet and extending across the width thereof above said dia.-

phragm section for iiexibly mounting the upper portion of said section, and an outwardly and downwardly curved attaching flange portion formed on the lower end of said diaphragm section and extending across the width of the tube sheet for offsetting thek 1 portion of said attaching flange.

5. In a boiler including a fire box having spaced inner and outer sheets, a mud ring connecting the lower edges of the inner and outer sheets, a Siphon supported by an upper inner sheet of the fire box and having substantially no inherent flexibility to compensate for expansion and contraction thereof, an inwardly inclined diaphragm section formed across the width of one of the inner sheets for mounting the lower end of said Siphon and having an outwardly and downwardly curved flange portion for attaching the lower'portion of said diaphragm section to the mud ring to provide free downward movement of the diaphragm section under influence of downward expansion of Said Siphon, and a reversely curved portion formed in Said diaphragm section and extending circumferentially of said Siphon connection with the diaphragm section to cooperate with the curved flange portion for providing expansive movement of the Siphon.

6. In a boiler including a fire box, comprising outer sheets and spaced inner sheets including a crown sheet and a tube sheet, a

mud ring connecting the lower edges of the inner and outer sheets, a water Siphon rigidly supported by the crown sheet and having a neck portion extending toward the tube sheet, an inwardly inclined diaphragm section formed on the lower portion of the tube sheet for mounting the neck of said Siphon and an outwardly and downwardly curved portion formed on the lower edge of said diaphragm section and extending substantially across the width of said tube sheet for attachment to the mud ring whereby downward thrust produced by expansion of said Siphon and imparted to said diaphragm section acts to flex said curved attaching portion.

7. In a boiler including a fire box comprising outer sheets and spaced inner sheets including a crown sheet and a tube sheet, a mud ring connecting the lower edges of the A inner and outer sheets, a Siphon rigidly supported by the crown Sheet and having a/neck portion extending toward the lower portion of the tube sheet, an inwardly inclined diaphragm section formed on the lower portion of the tube sheet and extending across the width thereof for mounting the neck of said Siphon, means formed in said tube sheet and extending across the width thereof above said diaphragm section for flexibly mounting the upper portion of said section and an outwardly and downwardly curved attaching flange portion formed on the lower end of said diaphragm section and extending across the width of said tube sheet for offsetting the plane of said section laterally of said attaching flange portion whereby downward thrust imparted to said section upon expansion of the siphon will be ,absorbed by the curved portion of Said attaching flange portion.

In testimony whereof I affix my signature.

HENRY V. STEVENS.

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